Keyboard, video and mouse (KVM) switches are known and used in a number of scenarios where a single keyboard and mouse is to control a number of remote computers. Thus, many transmitters (i.e., the remote computers) are connected to a single workstation including a keyboard, a monitor and a mouse. However, a consumer may also wish to operate in a reverse configuration where a single original video and/or audio source is used to control multiple video displays/monitors. Systems where a single video source can control multiple displays include the EMERGE MPX1500 HD MULTIPOINT EXTENDER manufactured and sold by AVOCENT CORPORATION, the assignee of the present application.
When using such a multi-display system, a transmitter (at an originating end) receives audio and/or video from an audio/video source (e.g., a cable/satellite set-top box, a computer, a DVD player (either original definition or high definition), a game console, a CD player or any other electronics device) (in either regular or high definition mode) and converts the audio and/or video signal (hereinafter AV signal) to a digitized, packetized form. (In configurations in which a transmitter receives video already in digital form, the transmitter need not digitize the video but only packetize it.) The transmitter then forwards (e.g., using at least one packet-switched network) the converted AV signal on to plural receivers which convert the digital AV signal back to its native form.
As transmission errors occur in such a configuration, retransmission of missing or corrupted information is required in order to keep the displays of the receivers in synchronization with the transmitter. However, it is possible to do more harm than good with a retransmission protocol.